Half an hour before three IDF mortar shells struck the Fakhura school in the Jabalya refugee camp, Ehud Barak warned of a disaster along the lines of the Qana massacre. Barak harbored no illusions. The forces on the ground are entangled with each other. The Golani Brigade is mired in an urban area rife with tunnels and burrows. At any moment, soldiers can fall victim to substantial harm. At any moment, many civilians are liable to inadvertently be killed.

As such, a fateful decision is called for: either resolution or expansion; a cease-fire or a full-scale aggressive operation whose goal is to topple Hamas.

Barak is not a big believer in removing Hamas from power. He learned the lessons of Iraq and Afghanistan, and is aware of the pitfalls of a simplistic policy of regime change. From the outset, he has held the view that the goal of the operation in Gaza needs to be restrained, defined and attainable. From his vantage point, the original objective of Operation Cast Lead was no more than reaching an enhanced truce over an extensive period of time, without the violations and arms smuggling.

Contrary to Avigdor Lieberman and Haim Ramon, the defense minister was not convinced that the operation's goals should be too ambitious. Eighteen months of quiet in the south is also an achievement, and will give Israel time to deal with strategic challenges far more complex than the challenge posed by Hamas. They will also move Israel closer to the point where it will be able to provide a technological response to the threat of projectiles. Even if Israel does not bring Ismail Haniyeh to his knees, a successful conclusion in Gaza will boost the deterrence factor and improve Israel's regional positioning.

But Barak is an experienced, battle-scarred warhorse. He remembers the disgrace of the Second Lebanon War, the imbroglio of "Grapes of Wrath," Operation Accountability and the second intifada. As such, he argues that nobody could predict how the fighting will end.

We advance from one decision-making stage to the next - from one fork in the road to the next, with each fork representing a choice between an exit ramp and a deepening or expansion of the operation.

The exit ramp proposed by France was initially torpedoed by Tzipi Livni. An exit opportunity following the aerial assault has passed. On the table now is a last chance for an exit before the operation turns into an all-out war against Hamas. If no agreed-on diplomatic formula or suitable political mechanism is in place by this weekend, Israel is liable to find itself in a war it did not desire: a war to topple Hamas.

Behind closed doors, Barak is extremely cautious. He is awed by the IDF and the man leading it, but he does not value his colleagues in the civilian leadership. One may glean from his statements that he is disturbed by the immaturity and inconsistency displayed by Livni, as well as her preoccupation with maintaining her grip on power in a time of war. Barak holds in high regard Olmert's intelligence, talent and experience, although he is concerned that the prime minister has his own reasons for not being eager to wrap up the operation. Barak has no doubt that if the diplomatic conduct were commensurate with the seriousness displayed on the military front, the situation today would be different.

The dilemma of the coming days is tremendous. Barak believes there are those suppressing the fact that toppling Hamas entails the occupation of Gaza, and the fact that if an exit point is not found quickly, there will be a need for a massive enlistment of reservists next week. Barak has not completely ruled out an escalation of the fighting, but it is not what he really wants. He is wary of a situation in which the government is not aware of the consequences of its decisions - decisions that could lead to Israel recapturing the entire Gaza Strip.

Barak has always been an either-or individual. His critics took him to task for his binary personality. And yet, the last time he viewed reality from a black-and-white point of view, he proved to be right. Barak's decision to take a risk in agreeing to the lull was shown to be a wise one. Though he did enable Hamas to arm itself with rockets capable of reaching Gedera, he also earned the quiet support of Egypt, the moderate Arabs and the Europeans.

Without the lull, Israel would not have the diplomatic backing and moral legitimacy necessary to deal a blow to Hamas. On the basis of that logic, perhaps Barak is also right this time. This weekend is not a leisurely weekend. It is a weekend of either-or. If Israel does not act properly and make the right choice, the current fork in the road is liable to lead it down a dead-end.

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